Copying machine

ABSTRACT

A copying machine of a through-slit-exposure type using a movable scanning mirror, a fixed table for placing an original to be copied and a fixed objective lens. The light source is movable and first and second mirrors are moved in orthogonal relationship and the velocities of the movements of these elements are predetermined. The mirrors are moved with the aid of belt means which is simple structure and ready to manufacture.

United States Patent [191 Kawakubo et al.

[451 Jan. 9, 1973 [541 COPYING MACHINE [75] Inventors: Knzuo Kawekubo, Kawasaki; Akira Kurahashl, Tokyo, both of Japan [73] Assignee: Canon Kabushiki Kaisha, Tokyo,

Japan [22] Filed: March 25, 1970 [21] Appl. No.: 22,443

[30] Foreign Application Priority Data April 12, 1969 Japan ..44/28558 April 12, 1969 Japan..' ....44/33414 [52] US. Cl ..355/8, 355/66 [51] Int. Cl. ..G03b 27/70 [58] Field of Search ..355/8,.65, 66

[56] References Cited UNITED STATES PATENTS 2,388,961 11/1945 Elliott at al ..95/4.5

Primary Examiner-John M. Horan Attorney-Ward, McElhannon, Brooks and Fitzpatrick [57] ABSTRACT A copying machine of a through-slit-exposure type using a movable scanning mirror, a fixed table for placing an original to be copied and a fixed objective 1 lens. The light source is movable and first and second mirrors are moved in orthogonal relationship and the velocities of the movements of these elements are predetermined. The mirrors are moved with the aid of belt means which is simple structure and ready to manufacture.

12 Claims, 7 Drawing Figures PATENTEDJAN ems 3.709.592

sum 1 BF 3 PATENTEUJAN 91923 3.709 592 sum 3 OF 3 COPYING MACHINE This invention relates to a copying machine, and more particularly to a through-slit-exposure type copying machine using a movable scanning mirror.

In the ordinary copying machine of the known type, an object to be copied must be illuminated whether the copying machine is directed to silver salt photography, microphotography or electronic photography.

For example, an electronic photocopying machine according to the prior art comprises means for electrically charging a photosensitive member having a photoconductive layer formed on the surface thereof, means for illuminating an object to be copied, means for developing a latent image with a developer containing a charged toner, means for transferring the visualized image onto sheets of transfer paper, means for fixing the transferred image and other means.

In general, the copying machine for use in offices has a tendency toward a smaller size and for this purpose, the most efficient is to provide a compact optical system for forming the optical image of an object to be copied.

To meet such requirement for compactness, there has been proposed a copying machine having an optical system through which the image of an object supported on a movable supporting table is optically formed on a moving photosensitive member. This type of copying machine, however, requires a complicated mechanism for providing synchronous relationship between the object supporting table and the photosensitive member, and is difficult and sometimes dangerous to operate. Moreover, when the object to be copied is a heavy one such as bulky or large book or the like, such copying machine is very inconvenient to manipulate and the load imparted to the machine by the heavy object will malaffect the mechanism of the machine.

To overcome these drawbacks existing in the prior art, the present invention proposes an optical system including a scanning mirror which is movable with respect to the object supported on a fixed supporting table so as to scan the surface of the object to be copied.

In order to achieve this, it is important to move the photosensitive member and scanning mirror in synchronism with each other. For this purpose, the present invention employs a first mirror for scanning the underside of the fixed object supporting table, a second mirror operatively associated with the first mirror and movable in such relationship that light from a source of light can always travel a predetermined distance, and belt means for driving these mirrors without using any complicated gear train or like transmission means.

Thus, the copying machine of the present invention employs the immovably fixed arrangement for the object supporting table and objective lens, and this provides a great convenience for setting any thick or bulky object in place on the supporting table and eliminates the need to provide any lens moving means which requires a high degree of accuracy in operation. The present invention thus provides great practical advantages for the industry of copying machines.

It is therefore an object of the present invention to provide a copying machine for use in offices.

It is another object of the present invention to provide a compact and less expensive copying machine of the type which has a fixed table for supporting an object to be copied.

It is still another object of the present invention to provide a copying machine in which a mirror scans the object to be copied and exposure is effected through a slit.

It is still another object of the present invention to provide a compact copying machine using a movable source of light and first and second mirrors movable in orthogonal relationship with each other.

It is yet another object of the present invention to provide a copying machine which is easyto manufacture, assemble and adjust as well as highly advantageous from the economic point of view.

It is still another object of the present invention to provide a copying machine in which mirrors are moved by belt means and which is simple in structure and ready to manufacture.

Other objects and features of the present invention will be readily appreciated by those skilled in the art when reading the following detailed description and appended claims.

The invention will be described by way of example in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing an example of the optical system applicable to the copying machine of the present invention;

FIG. 2 is a schematic diagram showing another example of the optical system applicable to the copying machine of the present invention;

FIG. 3 schematically shows the arrangement in a preferred form of the electronic photocopying machine incorporating the optical system of FIG. 1;

FIG. 4 shows the image transfer portion of the electronic photocopying machine of FIG. 3;

FIG. 5 is a schematic diagram showing still another example of the optical system applicable to the copying machine of the present invention;

FIG. 6 is a schematic diagram showing yet another example of the optical system applicable to the copying machine of the present invention; and

FIG. 7 schematically shows the arrangement in a preferred form of the electronic photocopying machine incorporating the optical system of FIG. 5.

' Referring to FIG. 1 which shows an embodiment of the optical system applicable to the copying machine of the present invention, there are an object to be copied l, a movable source of light 2 for illuminating the object l, a first movable mirror 3', a second movable mirror 4, an objective lens 5', a slit 6' and a photosensitive surface 7. While the following description is directed particularly to the case where the image of the object is reproduced to its original scale, it should be noted that the reproduction can be effected to an enlarged or reduced scale by suitably changing the.

The first and second mirrors 3 and 4' are moved at an equal velocity V in such a manner that they keep orthogonal relationship with each other, until the mirrors come to their respective positions as shown by the imaginary lines. In this position, the source of light 2' and the first mirror 3 complete their scanning operation. Thus, the object to be copied is projected through the objective lens 5' fixed in alignment with the optical axis U-U' of the second movable mirror 4 and through the slit 6' onto the photosensitive surface 7 which is moving horizontally at a velocity 2V i.e. double the mirror velocity, whereby an image of the object 1' is formed on the photosensitive surface. During the movement of the mirrors, the distance between the surface SS of the object and the center W of the lens 5, i.e., the distance S-T-UW and ST'U'-W is always maintained constant, so that the mirrors and the photosensitive surface are moved in complete synchronism with each other to thereby form a highfidelity image of the object on the photosensitive surface.

FIG. 2 shows another example of the optical system, which is very useful in that a copying machine can be made compact by incorporating such a system therein. In this alternative example, the photosensitive surface 7' is exposed to beams of light having an incident angle 0: through a slit. The source of light 2 and the first mirror 3 are moved in parallel to the surface SS of the object to be copied in the same way as described with respect to FIG. 1, whereas the second mirror 4' is moved in the direction U-U' at an angle to with respect to the vertical. This arrangement results in an advantage that the optical system can be made more compact than that of FIG. 1. The angle to is preferably 30 or less.

It will be appreciated that the examples of the optical system shown in FIGS. 1 and 2 arecharacterized in that the first and second mirrors are moved at the same velocity and in orthogonal relationship with each other.

Referring to FIG. 3, there is shown a preferred form of the electronic photocopying machine incorporating the optical system of FIG. 1. This copying machine is of the type which embodies the process of electronic photography developed by Applicant and covered by Applicants copending applications, Ser. Nos. 563,899, filed July 8, 1966; and 571,538, filed Aug. I0, 1966, that is, the process whereby a photosensitive member having a photoconductive layer and an insulating layer laminated on a base is subjected to primary electric charging, whereafter the picture to be copied is illuminated with radiant rays sensible by the photoconductive layer and contemporaneously therewith the photosensitive member is subjected to electric charging of the opposite polarity to the primary charging or a.c. corona discharge, and if desired, the entire surface of the photosensitive member is further illuminated with radiant rays sensible by the photoconductive layer so as to form an electrostatic latent image of high contrast. In FIG. 3, a housing 100 contains various means therewithin. A photosensitive drum I mounted on a rotatable shaft S comprises an electrically conductive base 11, a photoconductive layer 12 and an insulating layer 13 sequentially overlaid on the base 11. According to the process developed by us, it is also possible to use a translucent material for the base, not for the insulating layer, so that the object to be copied may be illuminated from inside the drum. A primary electric charger 2 comprises a corona electrode 21 and a shield plate 22 surrounding the electrode 21. The electrode 21 is connected to an unshown power source through an unshown lead wire so that a voltage may be applied with any desired polarity. A corona discharger 3 for effecting exposure contemporaneously with electric charging consists of a corona charging electrode 31 and a shield plate 32 surrounding the electrode 31 and hav ing an optically open upperportion designed to allow exposure to be effected contemporaneously with corona discharge. The corona charging electrode 31 is connected with an unshown power source so as to effect discharge of the opposite polarity to that of the electric charge applied by the charger 2 or a.c. corona discharge. The image of the object to be copied is illuminated by a scanning optical system to be described later through'the upper optical opening in the corona discharger 3 contemporaneously with the corona discharge effected by the corona discharger 3. Fully exposing means 4 comprises a source of light 41 and a shield plate 42, but this means 4 may be omitted as the case may be. Developing means 5 comprising a roll 52 and developing brushes 53, 54 and 55 is provided to apply electronic photocopying developer 51 to the photosensitive drum 1 so as to develop the electrostatic image formed thereon by the preceding process. An electric charger 6 comprises a corona discharging electrode 61 connected with an unshown power source, and a shield plate 62 surrounding the electrode 61. There are further provided an image transfer roll 7, a paper feeding table 89 supporting thereon a supply of transfer paper sheets 90, a paper feeding roll 91, a roll 92 connected with an unshown drive source, a transmission belt 93, and a pair of rolls 94 and 95 for feeding the transfer paper sheets. Drive rolls 72, 73 and 74 are provided to drive a conveyor belt 71 for conveying the transfer paper sheets which are fed one by one by the paper feeding roll 91 from the paper feeding table 89 through the pair of rolls 94 and 95, so that each transfer paper sheet is urged into intimate contact with the photosensitive drum 1 by the image transfer roll 7, whereby the visualized image on the drum 1 is transferred onto each transfer paper sheet. The transfer paper sheet having the image thus transferred thereon is carried to a fixing device 8 comprising a pair of spaced rolls 81 and 82 for driving a belt 83, and the paper sheet is then discharged out of the machine through an outlet 84. The discharged paper sheet is carried onto a paper receiving table 85. On the other hand, a cleaning roll 10 comprising an elastic member, a fur brush, etc. is provided for removing any residual developer remaining on the photosensitive drum 1 after the image transfer has been completed. Thus, a cycle of the copying process is completed.

Description will now be made in detail of the means for exposing the image of the object contemporaneously with the electric charging of the photosensitive surface through the upper optical opening formed in the discharger 3 for effecting the contemporaneous charging and exposure. An object to be copied P is supported on a supporting table A formed of a transl'ucent material and covered by an object setting cover which is opened and closed for setting the object in place by manually grasping a handle 151. The object P thus set in place on the supporting table A is illuminated by an illuminator B movable in parallel thereto and comprising a source of light 162 and a shield plate 164. The illuminator B is moved smoothly along a guide X mounted on the housing 100. The movement of the illuminator B is accomplished by a slide member 165 slidably mounted on the guide X and carrying thereon the illuminator B. A drive belt Y for advancing the illuminator B and a return belt Z for backing the illuminator B are connected to the shield plate 164, and the latter belt Z has one end thereof connected to return means L driven by a spiral spring or motor.

The letter C represents the first mirror which is smoothly movable in parallel to the object P along a guide H mounted on the machine housing 100. Such smooth movement of the first mirror C is accomplished by a slide member 152 slidably mounted on the guide H and carrying the first mirror C thereon. The slide member 152 has a downwardly extended projection 153, to which is secured a belt J for advancing the mirror C and a return belt Q for backing the mirror C. The return belt Q has one end thereof connected to return means L driven by a spiral spring or motor. The letter D represents the second mirror disposed so as to maintain orthogonal relationship with respect to the first mirror C, and the second mirror D is vertically movable with respect to the first mirror C so that the light from the source of light always travels the same distance between the surface of the object P and the photosensitive drum 1. The vertical movement of the second mirror D is achieved along a guide I by a slide member 155 slidably mounted on the guide I and carrying the second mirror D thereon. The slide member 155 has a lateral projection 156 to which is connected a belt K for advancing or lowering the second mirror D and a return belt 0 for backing the mirror D.

The photosensitive drum 1 is provided with a synchronizing drum M disposed coaxially therewith for synchronizing the rotation of the drum 1 with the movement of the first and second mirrors C and D. For this purpose, the belts J and K connected to the first and second mirrors C and D respectively have their respective other ends entrained and secured to the synchronizing drum M. In the illustrated embodiment, the belts J and K are united together at a point R so as to provide a unitary belt portion N, whose end is secured to the synchronizing drum M. The return belt 0 for the second mirror D has the other end thereof entrained on the synchronizing drum M in the opposite direction to the belts J and K or N and secured to that drum, while the return belt Q for the first mirror C is connected to the spring or motor-driven return means L as described previously. However, the return belt 0, as well as the return belt 0, may be entrained on the synchronizing drum M, and in that case the return drive source may be mounted within the drum M to thereby obtain the same result.

The photosensitive drum 1 is also provided with another synchronizing drum M for synchronizing the rotation of the photosensitive drum 1 and the movement of the, illuminator B. This synchronizing drum M is formed integrally with the synchronizing drum M and disposed coaxially therewith, but has a diameter twice as great as that of the drum M. The belt Y for advancing the illuminator B and the return belt Z for backing the same illuminator may be entrained on the synchronizing drum M in the opposite directions to each other and secured thereto, although the return belt 2 is shown connected to the spring or motor-driven return means L as described previously. If the return means L for the illuminator B takes the form of a drive system integral with the return means L for the first mirror C, then the diameter of the return means L must have a diameter doublethat of the return means L so that the amount of return of the illuminator B may be double that of the first mirror.

The forward movement of the illuminator B may also be accomplished by providing a rotatable drum assembly including two concentric drums 121 and 122 outlined by chain lines having diameters at the ratio of 2:1, and entraining and securing a belt Y to the greater-diametered drum 121 and a belt J to the smaller-diametered drum 122, the belt J being con nected to the belt J. In this case, the drum M and the belt Y need not be provided.

Between the synchronizing drums M and M and the shaft S or the photosensitive drum 1 there is provided an electromagnetic clutch, not shown. The unshown electromagnetic clutch is released from engagement by unshown detector means which detects the arrival of the first mirror C and illuminator B at their respective rightmost positions and the arrival of the second mirror D at its lowermost position. As a result, the synchronizing drums M and M are allowed to rotate in the opposite direction to that of the arrow by the reverse drive force of the return means L, whereby the first and second mirrors C, D and illuminator B are returned to their initial positions.

There are also provided a fixed projection lens E and deflection mirrors F and G for changing the path of light. The image of the object P illuminated by the illuminator B while being scanned by the first mirror C is reflected by the second mirror D and passed through the projection lens E so as to be reflected by the third and fourth mirrors F-G and reach the photosensitive layer on the photosensitive drum 1 through the optical opening in the contemporaneous charger-exposure means 3, thus forming an image on the photosensitive layer while it is contemporaneously subjected to the electric charging of the opposite polarity or a.c. corona discharge provided by the charger-exposure means 3. The copying machine of FIG. 3 also includes a button 14 for operating the machine, guide rolls 157 and 158 for the belt J, a guide roll 159 for the belt N, a guide roll 160 for the belt K, a guide roll 161 for the belt 0, a guide roll 166 for the belt 2, and guide rolls 167 and 168 for the belt Y.

The operation of the electronic photocopying machine shown in FIG. 3 will now be described. The insulating layer 13 on the photosensitive drum 1 is previously charged uniformly with positive or negative electric charge by the electric charge by the electric charger to so that electric charge of the opposite polarity to that charge may be captured in the interface between the photoconductive layer 12 and the insulating layer 13 or in the photoconductive layer. Subsequently, the image of the object to be copied isilluminated with radiant rays sensible by the photoconductive layer so as to be projected onto the surface of the electrically charged insulating layer 13, and contemporaneously therewith the same insulating layer is subjected to electric charging of the opposite polarity to that of the previous charging or a.c. corona discharge so as to form an electrostatic image of the original picture on the surface of the insulating layer 13 due to the surface potential difference resulting in accordance with the contrast of the original image. In this case, the illumination of the original image effected contemporaneously with the charging of the said opposite polarity or a.c. corona discharge is accomplished in the manner described hereunder. Since the rotation of the photosensitive drum 1 causes the rotatable drums M and M to rotate in the direction shown by the arrow, the belt N secured to the drum M is taken up thereby and the belt Y secured to the drum M' is taken up thereby, so that the first and second mirrors C and D connected to the belt N through belts J and K and the illuminator B connected to the belt Y are pulled rightwardly, downwardly and rightwardly, respectively, as viewed in FIG. 3, so as to scan and illuminate the original image until they reach their respective positions indicated by the imaginary chain lines. The original image is thus projected onto the photosensitive drum 1 through the discharger 3. If the original image is to be reproduced to its original scale, the illuminator B is moved at a velocity double that of the first mirror C because the diameters of the drums M and M are at the ratio of 1:2, whereby the surface of the object to be copied can be uniformly illuminated. The completion of the scanning is detected by the unshown detector means to thereby release the unshown electromagnetic clutch provided between the photosensitive drum 1 and the rotatable drums M and M. As a result, the rotatable drums M and M are released for free rotation and thereby the first and second mirrors C, D and the illuminator B are returned from the positions shown by the imaginary lines to their respective initial positions, by the return means L connected to the belt O which pulls back the first mirror D and by the return means I connected to the belt Z which pulls back the illuminator B, respectively. If the reproduced image is of the original scale, the illuminator B is returned at a velocity double that of the first mirror because the return means L and L are diametered at the ratio of 1:2. The photosensitive layer of the drum 1 is entirely illuminated through the whole surface exposure means 4 so that an electrostatic image having a high contrast is formed on the surface of the insulating layer 13. Further, the electrostatic image is developed into a visible image by a developer 51 composed mainly of electrically charged colored powder within the developing box 5, thereafter the visualized image is electrically charged with a desired polarity by the discharging electrode 61 of the electric charger 6. Subsequently, the image transfer paper sheets as indicated by 90 and stacked on the paper feeding table 89 are fed one by one by the feeding roll 91 so that the visualized image on the photosensitive drum 1 is transferred to each image transfer paper sheet by the image transfer roll 7. The transfer paper sheet to which the visualized image has been transfered by the transfer roll 7 is separated from the photosensitive drum 1 with one side edge of the paper sheet pinched between the transfer roll 7 and the separating belt 71 which extends along one end of the transfer roll 7 having a slightly greater length than the photosensitive drum 1, as shown in FIG. 4. The separating belt 71 is shown only at one end of the transfer roll 7, but it may be provided at either end of the roll 7. The transfer paper sheet is then conveyed by the belt 71 into the fixing device 8, where it is subjected to hot radiation for fixing. Thus there is provided a complete copy of the original image, which copy is then discharged into the receiving table through the outlet 84 formed in the machine housing 100.

Upon completion of the image transfer, the insulating layer 13 on the photosensitive drum 1 is cleaned by the cleaning roll 10 which removes any residual charged particles remaining on that layer, whereupon the photosensitive drum 1 is ready for another cycle of the copying operation.

While the above description has been made with respect to the case where copying is effected to the original scale, it should be noted that an enlarged or reduced scale of the reproduction can be realized by changing the velocity of movement of the various means in accordance with the intended scale.

FIGS. 5 and 6 illustrate further examples of the optical system used with the copying machine of the present invention.

In these examples, the optical system comprises an illuminator B horizontally movable with respect to the surface of the object P to be copied, a first mirror C for scanning the fixed object P, and a second or deflection mirror D for directing the image reflected by the mirror C to the photosensitive drum 1 through a fixed objective or projection lens E. The mirrors C" and D both have a width d required for the exposure through a slit and are disposed in orthogonal relationship with each other. The mirror C is moved at a velocity V in a downwardly inclined direction in a plane vertical to the surface of the object P, while the mirror D is moved at a velocity Vv in a direction along the optic axis passing through the mirror D and projection lens E. The velocity V is a composite velocity of Vh and Vv, where Vh represents the component of velocity which is parallel to the object P and Vv represents the component of velocity which is parallel to the optic axis.

Such an arrangement only requires the mirrors C" and D having a small width to be moved, and this leads to a simple construction of their drive mechanism as well as to a smaller number and smaller size of the moving parts, which also results in the provision of a copying machine which is compact in structure and very smooth in operation as well as economical to manufacture.

In FIGS. 5 and 6, there are also shown deflection mirrors F and G and photosensitive drum 1, and these are the same as those described with respect to FIG. 3. The optical system of FIG. 5 is directed to the case where the object P is scanned by the scanning mirror C" moving in parallel to the surface of the object, while the optical system of FIG. 6 relates to the case where the object P is scanned at an angle 0 with respect to the vertical. The example of FIG. 6 is useful to reduce the height of the scanning portion. In FIG. 6, the first mirror C scans the object P in the inclined direction V while the second mirror D is moved in orthogonal relationship with the first mirror C". After all, the two mirrors move in such relationship that the component Vh of the first mirrors velocity which is parallel to the object P and the second mirrors velocity Vv are at the ratio of 2: 1.

FIG. 7 illustrates another form of the electronic photocopying machine according to the present invention, which incorporates the optical system of FIG. 5. Like characters used in FIG. 7 designate like parts appearing in FIG. 3 and these similar parts will be omitted in the following description.

A holder 20 for holding the scanning mirror Cl is mounted on an inclined guide H1. The holder 20 has a pin 26 planted thereon to help the mirror Cl move along the inclined guide Hl while also helping the mirror Cl move along a slotted vertical guide member 24. A slotted horizontal guide member 27 is provided to horizontally guide the slotted vertical guide member 24. The mirror D is carried by a holder 155 which is slidably mounted on a vertical rod 1. Two synchronizing drums M and M whose peripheral speed ratio is 1:2 are mounted coaxially on the shaft S of the photosensitive drum 1. A belt Y has one end thereof secured to the larger drum M, and the other end of the belt Y or belt P extending therefrom via belt Y" is connected to the slotted vertical guide member 24 at 24. Two belts K and O are entrained on the smaller drum M in the opposite directions to each other and secured thereto at one end. The other ends of the belts K and O are connected to the lower and upper portions of a projection 156 extended from the second mirror holder 155.

Rotation of the photosensitive drum 1 causes the synchronizing drums M and M to rotate together, so that these drums M and M take up the belts Y' and K respectively, to thereby cause the mirrors Cl and D to move at the respective velocities Vh and Vv. Thus, the image of the object P is projected onto the surface of the photosensitive drum through the projection lens E and mirrors F and G.

The arrival of the illuminator B or mirror Cl (or mirror D) at its terminal position is electrically detected, whereupon the unshown clutch provided between the drums M, M and shaft S (or photosensitive drum 1) are released from engagement. Thereupon, the slotted vertical guide member 24 and accordingly the scanning mirror Cl are pulled back through the belt P by the return drive source N driven from motor or spiral spring, whereby the synchronizing drums M and M are rotated counter-clockwise through the belt Y to rewind the belt and thereby return the mirror D to its initial position.

Alternatively, the belt P may be replaced by a belt R as indicated by an imaginary line which is entrained on the synchronizing drum M. In this case, the drum M may contain therewithin the return drive means such as spiral spring.

If it is desired to move the illuminator B along the guide X concurrently with the scanning mirror C1, the belt Y connected to the illuminator B may be united to the belt Y at Y. The return of the illuminator B to its initial position is accomplished by the belt Z.

Instead of using the vertical and horizontal guide members 24 and 27, it is also possible to utilize the belt Y' so as to pull the scanning mirror holder 20 along the inclined guide rod H1 at a velocity approximate to the peripheral speed of the drum M.

With the described arrangement, a predetermined movement synchronous with the rotational movement of the photosensitive drum 1 can be readily imparted to the scanning mirror Cl and mirror D both having a small width required for the through-slit-exposure.

While the present invention has been described above with respect to the actual apparatus to which the process developed by us as mentioned before is applied, it will be apparent that the present invention is not limited to such process alone but applicable to other various processes including, for example, electric charging, exposing, developing and image-transferring involved in the photography using a photosensitive member having a photoconductive layer disposed on an electrically conductive substrate. The present invention is also applicable to the conventional copying machines of the ordinary type directed to microphotography, silver salt photography or the like, whereas description has been limited herein to the electronic photocopying machine.

As will be apparent from the foregoing disclosure, the copying machine of the present invention employs a fixed arrangement for the object supporting table and objective lens and this leads to a great convenience for setting any thick or bulky object in place as well as to the elimination of the need to provide any lens moving means which requires a high degree of accuracy.

Furthermore, in the example of FIG. 3, the equal velocity of the two mirrors leads to a simple operative relationship based on the velocity ratio of lzl and this only requires simple interlocking means such as belts without using any complicated cam or gear train. In addition, the second mirror can be small in size and light in weight. Thus, the present invention has great practical advantages in that it provides a copying machine which is simple to manufacture, assemble and adjust as well as economical and compact. Also, in the embodiment of FIG. 7, a predetermined movement synchronous with the rotation of the photosensitive drum 1 can be readily imparted to the scanning mirror Cl and mirror D both having a small width required for the through-slit-exposure.

What is claimed is:

l. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising,

a table for supporting thereon said original to be reproduced;

means for illuminating the surface of said original;

a first mirror movable at a predetermined angle with respect to the surface of said original; a second mirror movable in a direction different from that of said first mirror;

belt means for displacing said first mirror so as to scan the original on the supporting table;

belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors;

drive means for returning said first and second mirrors to their original positions after scanning;

a projection lens fixedly disposed in the path of light from the original for projecting the original image;

a slit for scanning the image of said original therethrough; and

a photosensitive member disposed adjacent said slit and movable at a predetermined velocity related to said first and second mirrors.

2. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising,

a table for supporting thereon said original to be reproduced;

means for illuminating the surface of said original;

a first mirror movable at a predetermined angle with respect to the surface of said original;

a second mirror movable in a direction different from that of said first mirror;

belt means for displacing said first mirror so as to scan the original on the supporting table;

belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors;

a projection lens fixedly disposed in the path of light from the original for projecting the original image;

a photosensitive drum moving at a predetermined velocity related to said first and second mirrors;

a synchronizing drum disposed coaxially with respect to said photosensitive drum and a clutch interposed therebetween, said belt means for moving said first and second mirrors being connected to said synchronizing drum so as to move said mirrors with the movement of said photosensitive drum;

means for detecting the completion of said scanning effected by said first and second mirrors to release said clutch from engagement;

belt means for returning said second mirror to its initial position after scanning; and

belt means for returning said first mirror to its initial position after scanning.

3. A through-slit-exposure type copying machine as defined in claim 2 wherein said belt means for returning said first mirror are entrained on said synchronizing drum in the opposite direction to said belt means for advancing said first mirror, and said synchronizing drum contains return drive means therewithin.

4. A through-slit-exposure type copying machine as defined in claim 2, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporaneously with electric charging, developing means, image transfer means, and cleaning means, these means being sequentially disposed along the surface of said photosensitive drum, and means for feeding sheets of transfer paper to said image transfer means.

5. A through-slit-exposure type copying machine as defined in claim 2, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporaneously with electric charging, means for exposing the entire surface of said photosensitive drum to radiant rays sensible by said photoconductive layer, developing means, image transfer means and cleaning means, these means being disposed along the surface of said photosensitive drum.

6. A through-slit-exposure type copying machine as defined in claim 2, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, slit means, developing means, image transfer means, and cleaning means, these means being disposed along the surface of said photosensitive drum, and means for feeding sheets of transfer paper to said image transfer means.

7. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising,

a table for supporting thereon said original to be reproduced;

means for illuminating said original; I

a first mirror movable in parallel relation with respect to the surface of said original;

a second mirror movable in a direction different from that of said first mirror;

belt means for displacing said first mirror over a distance of one half the length of said original supporting table for scanning the original placed thereon; belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors;

drive means for returning said first and second mirrors to their original positions after scanning;

a projection lens fixedly disposed in the path of light from the original for projecting the original image;

a slit for scanning the image of said original therethrough; and

a photosensitive member disposed adjacent said slit and movable at a predetermined velocity related to said first and second mirrors.

8. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising,

a table for supporting thereon said original to be reproduced;

means for illuminating said original;

a first mirror movable in parallel relation with respect to the surface of said original;

a second mirror movable in a direction different from that of said first mirror;

belt means for displacing said first mirror over a distance of one half the length of said original supporting table for scanning the original placed thereon;

belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors;

a projection lens fixedly disposed in the path of light from the original for projecting the original image;

a photosensitive drum moving at a predetermined velocity related to said first and second mirrors;

a synchronizing drum disposed coaxially with respect to said photosensitive drum and a clutch interposed therebetween, said belt means for moving said first and second mirrors being connected to said synchronizing drum so as to move said mirrors with the movement of said photosensitive drum;

means for detecting the completion of said scanning effected by said first and second mirrors to release said clutch from engagement;

belt means for returning said second mirror to its initial position after scanning; and

belt means for returning said first mirror to its initial position after scanning.

9. A through-slit-exposure type copying machine as defined in claim 8, wherein said belt means for returning said first mirror are entrained on said synchronizing drum in the opposite direction to said belt means for advancing said first mirror, and said synchronizing drum contains return drive means therewithin.

10. A through-slit-exposure type copying machine as defined in claim 8, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporaneously with electric charging, developing means, image transfer means, and cleaning means, these means being sequentially disposed along the surface of said photosensitive drum, and means for feeding sheets of transfer paper to said image transfer means.

1 1. A through-slit-exposure type copying machine as defined in claim 8, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporaneously with electric charging, means for exposing the entire surface of said photosensitive drum to radiant rays sensible by said photoconductive layer, developing means, image transfer means and cleaning means, these means being disposed along the surface of said photosensitive drum.

12. A through-slit-exposure type copying machine as defined in claim 8, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, slit means, developing means, image transfer means, and cleaning means, these means being disposed along the surface of said photosensitive drum, and means for feeding sheets of transfer paper to said image transfer means. 

1. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising, a table for supporting thereon said original to be reproduced; means for illuminating the surface of said original; a first mirror movable at a predetermined angle with respect to the surface of said original; a second mirror movable in a direction different from that of said first mirror; belt means for displacing said first mirror so as to scan the original on the supporting table; belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors; drive means for returning said first and second mirrors to their original positions after scanning; a projection lens fixedly disposed in the path of light from the original for projecting the original image; a slit for scanning the image of said original therethrough; and a photosensitive member disposed adjacent said slit and movable at a predetermined velocity related to said first and second mirrors.
 2. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising, a table for supporting thereon said original to be reproduced; means for illuminating the surface of said original; a first mirror movable at a predetermined angle with respect to the surface of said original; a second mirror movable in a direction different from that of said first mirror; belt means for displacing said first mirror so as to scan the original on the supporting table; belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors; a projection lens fixedly disposed in the path of light from the original for projecting the original image; a photosensitive drum moving at a predetermined velocity related to said first and second mirrors; a synchronizing drum disposed coaxially with respect to said photosensitive drum and a clutch interposed therebetween, said belt means for moving said first and second mirrors being connected to said synchronizing drum so as to move said mirrors with the movement of said photosensitive drum; means for detecting the completion of said scanning effected by said first and second mirrors to release said clutch from engagement; belt means for returning said second mirror to its initial position after scanning; and belt means for returning said first mirror to its initial position after scanning.
 3. A through-slit-exposure type copying machine as defined in claim 2 wherein said belt means for returning said first mirror are entrained on said synchronizing drum in the opposite direction to said belt means for advancing said first mirror, and said synchronizing drum contains return drive means therewithin.
 4. A through-slit-exposure type copying machine as defined in claim 2, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporaneously with electric charging, developing means, image transfer means, and cleaning means, these means being sequentially disposed along the surface of said photosensitive drum, and means for feeding sheets of transfer paper to said image transfer means.
 5. A through-slit-exposure type copying machine as defined in claim 2, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporaneously with electric charging, means for exposing the entire surface of said photosensitive drum to radiant rays sensible by said photoconductive layer, developing means, image transfer means and cleaning means, these means being disposed along the surface of said photosensitive drum.
 6. A through-slit-exposure type copying machine as defined in claim 2, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, slit means, developing means, image transfer means, and cleaning means, these means being disposed along the surface of said photosensitive drum, and means for feeding sheets of transfer paper to said image transfer means.
 7. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising, a table for supporting thereon said original to be reproduced; means for illuminating said original; a first mirror movable in parallel relation with respect to the surface of said original; a second mirror movable in a direction different from that of said first mirror; belt means for displacing said first mirror over a distance of one half the length of said original supPorting table for scanning the original placed thereon; belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors; drive means for returning said first and second mirrors to their original positions after scanning; a projection lens fixedly disposed in the path of light from the original for projecting the original image; a slit for scanning the image of said original therethrough; and a photosensitive member disposed adjacent said slit and movable at a predetermined velocity related to said first and second mirrors.
 8. A copying machine for optically scanning an original by the use of a mirror and exposing through a slit comprising, a table for supporting thereon said original to be reproduced; means for illuminating said original; a first mirror movable in parallel relation with respect to the surface of said original; a second mirror movable in a direction different from that of said first mirror; belt means for displacing said first mirror over a distance of one half the length of said original supporting table for scanning the original placed thereon; belt means for displacing said first and second mirrors keeping an orthogonal relationship formed by respective normal lines of the mirrors and changing relative distance between the two mirrors; a projection lens fixedly disposed in the path of light from the original for projecting the original image; a photosensitive drum moving at a predetermined velocity related to said first and second mirrors; a synchronizing drum disposed coaxially with respect to said photosensitive drum and a clutch interposed therebetween, said belt means for moving said first and second mirrors being connected to said synchronizing drum so as to move said mirrors with the movement of said photosensitive drum; means for detecting the completion of said scanning effected by said first and second mirrors to release said clutch from engagement; belt means for returning said second mirror to its initial position after scanning; and belt means for returning said first mirror to its initial position after scanning.
 9. A through-slit-exposure type copying machine as defined in claim 8, wherein said belt means for returning said first mirror are entrained on said synchronizing drum in the opposite direction to said belt means for advancing said first mirror, and said synchronizing drum contains return drive means therewithin.
 10. A through-slit-exposure type copying machine as defined in claim 8, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporan-eously with electric charging, developing means, image transfer means, and cleaning means, these means being sequentially disposed along the surface of said photo-sensitive drum, and means for feeding sheets of transfer paper to said image transfer means.
 11. A through-slit-exposure type copying machine as defined in claim 8, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, discharging means for exposing said photosensitive drum to radiant rays sensible by said photoconductive layer contemporaneously with electric charging, means for exposing the entire surface of said photosensitive drum to radiant rays sensible by said photoconductive layer, developing means, image transfer means and cleaning means, these means being disposed along the surface of said photosensitive drum.
 12. A through-slit-exposure type cOpying machine as defined in claim 8, wherein said photosensitive drum comprises a substrate, and a photoconductive layer and a transparent insulating layer sequentially laminated on said substrate, and wherein said machine further includes electrically charging means, slit means, developing means, image transfer means, and cleaning means, these means being disposed along the surface of said photosensitive drum, and means for feeding sheets of transfer paper to said image transfer means. 